Heat actuated pumps



1963 c. D. Ma cRAcKEN HEAT ACTUATED PUMPS Filed March 28. 1957 2 Sheets-Sheet 1 INVENTOR; CALVIN D. MACCRACKEN ATTORNEY Jan. 15, 1963 c. D. M cRAcKEN HEAT ACTUATED PUMPS 2 Sheets-Sheet 2 Filed March 28. 1957 INVENTOR. CALVIN D. MACCRACKEN ATTORNEY United States Patent York Filed Mar. 28, 1957, Ser. No. 649,061 11 Claims. (Cl. 103-455) This invention relates to improvements in pumps, and particularly to an improved heat-actuated pump, referred to herein as a thermopump.

It has previously been proposed to make a heat-actuated pump comprising a closed system of vessels defining separate compartments which are connected by liquid and vapor conduits. In these separate compartments, liquid is alternately vaporized and condensed to produce volumetric changes within the pump. By connecting the system to a liquid supply source and a delivery point through a pair of check valves, these volumetric changes can be utilized to induce liquid flow, as in US. patent to Kleen, No. 2,553,817. Alternatively, these volumetric changes can be transmitted through a diaphragm or the like to in duce liquid flow, as in the system described in copending application Serial No. 564,442, filed February 9, 1956, now Patent No. 2,918,219, assigned to the assignee of the present invention.

The present invention has a general ob ect the provl sron of an improved thermopump characterized by slmplicity and economy of manufacture as well as by efficient and troublefree operation.

In accordance with preferred embodiments of the invention, the foregoing and other related objects and advantages are attained in a thermopump wherein the principal parts are enclosed within a single outer shell, and the various chambers or compartments of the pump are defined by partitions dividing up the space. inside the shell. In such an arrangement, the problem of leakageis not material because any leakage that may occur between the several compartments will not materially affect the operation and will not involve loss of liquid from the pump. Moreover, such a configuration eliminates the need for certain connecting tubes and components required in systems wherein the principal parts are completely separate and self-contained.

A more complete understanding of the invention, and of further objects and features thereof, can be obtained from the following description of illustrative embodiments thereof, when considered in connection with the accompanying drawing, wherein FIGURE 1 is a sectional elevation of a thermopump embodying the invention,

FIGURE 2 is a sectional plan view of the pump of FIG- URE 1, taken on the line 22 of FIGURE 1.

FIGURE 3 is a sectional elevation of an alternative embodiment of the invention, I

FIGURE 4 is a sectional plan view of the pump of FIGURE 3, taken on the line 44 of FIGURE 3, and

FIGURE 5 is a sectional elevation of a further embodiment ofthe invention.

Referring to FIGURES 1 and 2 of the drawing, a thermopump embodying the invention is shown to comprise an outer shell in the form of an upright cylinder which encloses the various compartments of the pump as described hereinafter.

A cylindrical wall 12 at the center of the shell 10 defines a cavity or passage 14 which is open at both ends. This space 14 either will accommodate an electrical cartridge heater element 16, or may serve as a flue for conducting hot gases from any suitable source, as in embodiments of the invention described hereinafter. case, heat for operating the pump will be transferred through the wall 12.

In either,

The-space inside the shell 10 is divided into several compartments or chambers by partition means including a lateral partition 18 midway between the ends of the shell 10. Below the lateral partition 18, the central wall 12 is surrounded by a second cylindrical partitioning element 20 of slightly larger diameter to define an annular compartment 22 between the partition 20 and the inner wall 12. This. compartment, 22 serves as a vaporizing compartment within which to vaporize liquid by heat passing through, the wall 12.

The annular space 24 within the shell 10 and outside of the partition 20 constitutes a compartment within which to collect vapor formed in the vaporizing compartment. Vapor transfer passages between the vaporizing compar ment 22 and the vapor, collecting compartment 24 are provided bya plurality of holes 26 in the upper part of the intermediate partition 20. Liquid transfer passages between the vaporizing and collecting compartments are provided by a plurality of holes 28 in the lower portion of the partition 20.

The remaining space within the shell 10 above the partitions 18 constitutes a compartment 30* within which to condense vapor collected in the collector compartment 24. A liquid transfer passage 32 between the vapor collection compartment 24 and the condenser compartment 30 isdefined by a tube 34 extending through the lateral partition 18 from the lowermost part of the vapor collecting compartment 24 into the condenser compantment 30.

'Avapor transfer passage 36 between the vapor collecting compartment 24 and the condenser compartment 30 is provided by a U-shaped tube 38 which extends downwardly from the upper portion of the collector compantment and thence upwardly through the partition and into the condenser compartment.

The means for transferring volumetric changes from inside. to outside the pump shell 10 comprises an inlet tube 40 which extends through the shell 10 into the condenser compartment 30. The inlet is connected to a check valve 42 which will permit liquid flow only into the condenser compartment andnot outwardly therefrom. An outlet tube 44 extends from the condenser on the opposite side ofthe shell 10, and also is connected to a check valve 46 forallowing liquid flow only out of the condenser and not in the opposite direction.

The pump is filled initially through a top fill opening 48 which communicates with the condenser compartment 30. The fill opening 48 is closed by a threaded cap 50 which screws onto a collar 52 extending upwardly around the opening 48. With the fill cap 50 removed, a priming charge of the liquid to be pumped can be poured in through the opening 48.

When the pump is operated, heat supplied through the wall 12 will vaporize liquid in the annular compartment 22. As vapor forms in the compartment 22, it will flow through the outlet, holes 26 into the collecting compartment 24. The vapor being collected will force liquid to flow downwardly'out of the compartment 24, upwardly through the passageway 32 into the condenser compartment 30, and out of the condenser 30 through the pipe 44 and the check valve 46. A small amount of liquid also will be displaced from the tube 38 as vapor collects therein.

The collection of vaporwill continue, with the liquid levels in the; compartment 24 and passage 36 continuing. to fall, until the vapor reaches the lower portion of the tube 38. Once the vapor level reaches the lowermost point in the U-tube 38, the hydrostatic balance between liquid and vapor pressures in the compartment 214 will be lost, and liquid. will start to flow down through the passage 32 and upwardly into the compartment 24, forcing vapor ahead of it through the tube 38 into the condenser compartment 30. As the vapor contacts the relatively cool liquid in the condenser compartment 30, rapid condensation will occur. This will immediately result in an inrush of liquid through the check valve 42 and pipe 40 to fill the space formerly occupied by the condensed vapor. As soon as the pump completely refills, the foregoing cycle will repeat.

The embodiment shown in FIGURES 1 and 2 has particular application in systems where it is desired to add substantial amounts of heat to the liquid being pumped. Since the passageway 14 extends through the center of the condenser compartment 30, it is evident that some of the heat from the cartridge 16 will pass into the liquid in the condenser and raise its temperature. "Of course, the relative sizes of the compartments 22, 30 and the distribution of heat thereto will be selected to insure suflicient temperature differential for condensation to occur in the condenser.

It'can be seen that the pump shown in FIGURES 1 and 2 has the distinct advantage of minimizing the number of potential leakage points at which liquid can be lost from'the system. -As compared with a system wherein all of the compartments 22, 24, 30 are defined by separate vessels with individual connecting tubes therebetween, the present'invention provides a pump wherein partitions or walls common to several compartments are utilized, thereby minimizing the potential leakage points. Furthermore, it is not essential to have absolutely leak-tight separation between the compartments, as small leaks between compartments within the pump will not interfere appreciably with the operation of the pump and will not result in any loss of system liquid.

Another feature of the pump shown in FIGURES 1 and 2 is the extension of the vapor transfer tube 38 into the condensing compartment 30, so that the tube 38 is immersed in the condensing liquid. The significance of this is in relation to noise associated with pump operation.

For certain applications, a pump is required which is essentially noiseless in operation. For example, one application of the pump disclosed herein is for circulating liquid through a flexible heat-exchange panel (e.g., a bed covering). When used in a bedroom, this requires a minimum of noise from the liquid circulator. While the thermopump has no motor noise or other comparable noise such as would be expected with a conventional motor-driven pump, there is a possibility of some noise being developed when the vapor condenses. It has been found, however, that the condensation noise'can be substantially eliminated if the condensation takes place within the vapor transfer tube, rather than upon discharge of the vapor into the condensing liquid. By making the vapor tube of heat conductive material and extending into the condensing compartment in contact with the condensing liquid so that the vapor tube walls will be kept cool, condensation will be caused to occur within the tube, and noise from the pump substantially decreased. In order to have sufiicientheat transfer surface to insure complete condensation with the vapor tube, it is sometimes necessary to make the vapor tube longer than the vertical height available within the condensing compartment. In such instances, the tube can be bent and run laterally in the condensing compartment the required distance.

FIGURES 3 and 4illustrate a further embodiment of the invention, particularly for applications wherein no auxiliary heating of the liquid is required. An illustration is also given in these figures of the use of hot flue gas from a burner or the like for actuating the pump.

In the pump shown in FIGURES 3 and 4, the outer shell comprises cylindrical side walls 52, an integral bottom plate 54 and,'preferably, a removable cover plate 56. The cover 56 may be clamped to a flange 58 on the wall 52 by nuts and bolts 60 or. the like to provide ready access to the internal parts described hereinafter. A gasket 4 62 between the cover 56 and the flange 58 provides a liquid-tight seal between the parts 56, 58.

A flue or chimney passage 14 is defined by a wall 12 which extends upwardly through the shell 10 from below the bottom 54 to above the cover 56, to conduct hot gases from a burner 64 of any suitable type. This central wall 12 may be permanently attached to the bottom 54, and fit snugly in a suitable opening in the cover 56. An O-ring 66 or the like insures a leak-tight joint between the wall 12 and the cover 56.

The wall 12 is surrounded by a cylindrical partition 20 to define the vaporizing compartment 22. A liquid inlet to the vaporizing compartment 22 is provided by an opening 68 in a housing 70 appended to the lower portion of the partition 20. The housing 70 contains a valve ball 72 which will permit liquid to flow into but not out of the compartment 22.

A further cylindrical partition 74 extends downwardly from the cover 56, surrounding and spaced from the vaporizing compartment wall 20, and terminating just above the bottom 54. This partition 74 cooperates with the partition 20 to define an annular vapor collecting compartment 24. As before, vapor transfer passages between the vaporizing compartment 22 and the vapor collecting compartment 24 are provided by a plurality of holes 26 in the upper part of the intermediate partition 20. The vaporizing compartment 24 may also contain an annular float 76 for separating the liquid and vapor in the collector 24, as described in US. Patent to Coleman, 2,744,470.

The remaining annular space within the shell and outside of the cylindrical partitions 74 constitutes the condenser compartment 30. Since the wall 74 of the collector compartment 24 terminates above the bottom plate 54, free communication is provided between the lowermost part of the vapor collecting compartment 24 and the condenser compartment 30 below the lower end of the wall 74.

Vapor transfer coupling between the vapor collecting compartment 24 and the condenser compartment 30 is provided by a plurality of passageways each comprising a duct 78 formed in the partition 74 and opening into the upper portion of the collector compartment 24 through a port 80. Near the lower end of the partition 74, the duct 78 opens laterally through a connecting elbow 82 into a tube 84 of heat conductive material which extends upwardly into the condenser compartment 30 in contact with the condensing liquid therein. Advantageously, the elbow 82 may be formed in an appendage 8-6 which extends into the chamber 30 and carries the tube 84 as a press-fitted insert.

The operation of the pump shown in FIGURES 3 and 4 is essentially the same as that already described for the pump of FIGURES 1 and 2.; Heat passing through the Wall 12 will vaporize liquid in the compartment 22, and the vapor will collect in the adjacent compartment 24, driving liquid out of the compartment 24 under the partition 74 and out of the condenser 30 through the check valve 46. When the liquid level drops to the elbow 82 of any one of the vapor passages, the pump will recycle.

The purpose of the multiple vapor passages is to insure proper operation of the pump the vertical axis of the pump is tilted. Where the generating, collecting and condensing compartments are concentrically arranged as in FIGURES 3 and 4, it results in the vapor passage being displaced substantially from the vertical center line of the pump. It can be seen, for example, that if a pump in the position shown in FIGURE 3 Were to be rotated, say, 30 degrees in a counterclockwise direction as viewed in the drawing, one portion of the lower edge of the compartment wall 74 will eventually be above the vapor passage elbow at the opposite side of the pump. This would allow vapor to escape under the bottom edge of the wall 74 and the pump would not recycle. By having multiple vapor passages at spaced points about the vapor collector compartment 24, one such passage will be eifective to cycle the pump even though the pump may be tilted from the vertical.

It is also preferable to make the partition 74 of heat insulating material,- such as a plastic material, to reduce heat losses from the collector compartment to the condenser compartment.

It will, of course, be understood thatthe pump shown in FIGURES 3 and 4 can be operated with an electrical heater cartridge in place of the burner 64, as illus trated in FIGURE 1.

In accordance with a further embodiment of the invention, as illustrated in FIGURE 5, the thermopump of the present invention can be arranged to transfer volumetricchanges, from inside. the pump to a separate external circuit without liquid transfer, whereby different Liquids can be used in the pump and in the pumping circuit. To this end, the liquid retaining function of one rigid wall of the main pump shell is supplanted by a displacement element such as a flexible diaphragm.

In the embodiment shown in FIGURE 5, the pump shell comprises cylindrical side walls 52 and a cover plate 56, as in FIGURE 3. However, in FIGURE 5, the bottom wall of the pump shell, comprises a flexible diaphragm 90 of rubber or the like, held in place by a clamping ring 92.

The vapor generator partition 20 has -a liquid inlet opening 68 in the bottom and is provided with a ball check 72. In the present embodiment, an electric heater cartridge 16 is provided for actuating the pump.

The side walls 52 and bottom portion 90 of the pump shell are entirely enclosed within an outer cylindrical housing 96, which may be conveniently assembled with the main pump shell by nuts and bolts 60. This housing 96 cooperates with the pump walls 52, 90 to define a compartment- 98 through which to circulate the liquid being pumped. Inlet and outlet tubes 40, 44 ad check valves 42, 46 communicate with this compartment 98.

During operation of the pump of FIGURE 5, the volumetric changes which are produced inside the pump shell by alternate vaporization and condensation of liquid will cause the diaphragm 90-to flex up and down, thereby expelling liquid from the outside compartment 98 through the pipe 44 during vaporization and drawing liquid into this compartment through the pipe 40 during condersation. This permits the use of different liquids in the pump and in the external circuit, as where the liquid to be circulated does not have the proper boiling temperature, for example.

While the pump liquid does not circulate through the external circuit, the latent heat released in the condenser compartment 30 during condensation will pass through the walls 52, 90 into the compartment 98 and be carried away by the liquid circulating in the external circuit.

What is claimed is:

1. In a thermally actuated pump of the type in which alternating volumetric changes are produced by alternately vaporizing liquid. in a first portion of said pump and condensing the vaporized liquid in a second portion of said pump, in combination, an outer shell having space therein, first partition means in said shell defining a first said other compartments, and having a second opening therein affording communication: for vapor flow from the upper part of said first compartment to the upper part of said second compartment, means defining a liquid conductive passagway between said third compartment and the lower part of said second compartment, means defining a U.-shaped vapor conduit extending downwardly from the upper, part of said second compartment and then upwardly above said second compartment and to said third compartment, a portion of said outer shell adjacent to said third compartment comprising a displaceable element. constituting means for transferring volumetric changes from inside to outside said shell, and conduit means attached to said shell for tnansferring volumetric changes from said pump.

2. The invention defined in claim 1, including means defining a liquid chamber outside of said shell and adjacent to said displaceable element, whereby to provide for a tnansfer of volumetric changes from the space inside said shell to the space inside said chamber. 7 3. In a thermally actuated pump of the type in which alternating vdlumetric changes are produced by alternately vaporizing liquid in a first portion of said pump and condensing said vaporized liquid in a separate second portion of said pump, in combination, a closed outer shell, first partition means in said shell defining an annular first compartment extending into the lower part of said shell in which to vaporize liquid by heating, second partition means defining an annular second compartment surrounding said first compartment inwhich to collect vapor formed in said first compartment, said first and second compartments together encompassing only a part of the total space within said shell, at least a part of the remaining space inside said shell constituting a third compartment Within which to condense vapor collected in said second compartment, said third compartment having a portion higher than the second compartment, said first partition means having openings therein affording communication for liquid flow between the lower part of said first compartment and another of said compartments and affording communication for vapor flow from the upper part of said first compartment to the upper part of said second compartment, means defining a liquid conductive passageway between said third compartment and the lower part of said second compartment, means defining a -U-shaped vapor conduit extending downwardly from the upper part of said second compartment and then upwardly above said second compartment and to said third compartment, and flexible diagragm means in said-shell for transferring volumetric changes from inside, to outside said shell.

4. In a thermally actuated pump of, the type in which alternating volumetric changes are produced by altercompartment in which to vaporize liquid by heating and second partition meansin said shell defining a second compartment, said second compartment extending upwardly in said shell at least to the level of the top of said first compartment and being adjacent to said first compartment in which to collect vapor formed in said first compartment,

said firstand second compartments together encompassing only a part of the total space within said shell, at least a part of the remaining space inside said shell constituting a third compartment within which to condense vapor collected in said second compartment, said third compartment having a portion at a higher level than the top of said second compartment, said first partition means having an opening therein affording communication for liquid flow between the lower part .of said first and one of nately vaporizing liquid in a first portion of said pump and condensing said vaporized liquid in a second portion of said pump, the improvement which comprises a housing having a first compartment therein for vaporizing the liquid and a second compartment communicating with the upper portion of said first compartment for collecting the vapor in said second compartment, said pump including a-third compartment having liquid therein, a vapor transfer tube extending from said second compartment for a substantial distance into said third compartment so asto be immersed in the liquid contained in said third compartment, the portion of said vapor transfer tube which is immersed in the liquid contained in said third compartment being formed of material of good heat conductivity in contact with said liquid to insure good transfer of heat through the walls of said tube, whereby to induce vapor condensation to occur within said tube. V

5. In a thermally actuated pump of the type in which alternating volumetric changes are produced by alternately vaporizing liquid in a first portion of said pump and condensing, said vaporized liquid in a separate second portion of said pump, in combination, a closed cylindrical outer shell having a cylindrical cavity extending into the central portion of said shell, a first lateral partition d1viding the space inside said shell into upper and lower portions, a cylindrical partition in said lower portion surrounding said cylindrical cavity and cooperating with said shell to define a first annular compartment in the central part of said lower portion in which to vaporize liquid by heating, said lateral partition and said cylindrical partition defining a second annular compartment 1n-the lower portion of said shell surrounding said first compartment in which .to collect vapor formed in said first compartment, said space above said lateral partition constituting a third compartment within which to condense vapor collected in said second compartment, said cylindrical partition having openings therein alfording communication for liquid flow between the lower parts of said first and second compartments and affording communication for vapor flow from the upper part of said first compartment to the upper part of said second compartment, means defining a liquid conductive passageway between said third compartment and the lower part of said second compartment,.means defining a U-shaped vapor conduit extending downwardly from the upper part of said second compartment and, then upwardly above said second compartment and to said third compartment, and volumetric change transferring means for said shell for transferring volumetric changes from inside to outside said shell.

6. In a thermally actuated pump of the type in which alternating volumetric changes are produced by alternately vaporizing liquid in a first portion of said pump and condensing said vaporized liquid in a separate second portion of said pump, in combination, a closed cylindrical outer shell having a cylindrical cavity extending into the central portion of said shell, a first lateral partition dividing thespace inside said shell into upper and lower portions, a cylindrical partition in said lower portion surrounding said cavity and cooperating with said shell to define a first annular compartment in the central part of said lower portion in which to vaporize liquid by heating, said lateral partition and said cylindrical partition defining a second annular compartment in the lower portion of said shell surrounding said first compartment in which to collect vapor formed in said first compartment, said space above said lateral partition constituting a third compartment within which to condense vapor collected in said second compartment, said cylindrical partitionhaving openings therein affording communication for liquid flow between the lower parts of said first and second compartments and afiording communication for vapor fiow from the upper part of said first compartment to the upper part of said second compartment, a liquid conduit extending through said lateral partition from the lower portion of said second compartment to the lower portion of said third compartment, a U-shaped vapor conduit disposed within said second compartment and extending downwardly from the upper portion of said second compartment and then upwardly through said lateral partition into said third compartment, and

an inlet tube and an outlet tube communicating through said shell with said third compartment.

- 7. In a thermally actuated pump of the type in which alternating volumetric changes are produced by alternately vaporizing liquid in a first portion of said pump and condensing said vaporized liquid in a separate second portion of said pump, in combination, a closed outer shell, first partition means in said shell defining a first annular compartment centrally disposed in said shell in which to vaporize liquid by heating, second partition means defining a second annular compartment surrounding said first compartment in which to collect vapor formed in said first compartment and a third annular compartment surrounding said second compartment in which to condense vapor collected in said second com- 8 partment, said third annular compartment having a portion at a higher elevation than the upper part of said second compartment, said first partition means including a cavity extending vertically through the center of said shell and having a wall of good heat conductivity constituting one of the walls of said first compartment, said first partition means other than said cavity having openings therein affording communication for liquid flow to the lower part of said first compartment from the lower part of another of said compartments and afiording communication for vapor flow from the upper part of said first to the upper part of said second compartment, means alfording a liquid conductive passageway between said third compartment and the lower part of said second compartment, means defining a plurality of U-shaped vapor conduits extending downwardly from the upper part of said second compartment and then upwardly above said second compartment and extending into said third compartment, said U-shaped vapor con-' duits being positioned on opposite sides of the center of the pump and conduit means connected to said shell.

8. In a thermally actuated pump of the type in which alternating volumetric changes are produced by alternately collecting vaporized liquid in a first portion of said pump and condensing the vaporized liquid in a second portion of said pump, in combination, a closed outer shell, a first cylindrical partition in said shell encompassing a first central compartment inside said shell in which to vaporize liquid by heating, a second cylindrical partition surrounding said first partition and defining therewith an annular second compartment adjacent.to said first compartment and surrounding said first compartment in which to collect vapor formed in said first compartment and defining with said shell an annular third compartment in which to condense vapor, said annular third compartment having a portion at a higher elevation than said second compartment, said first partition having opening portions afiording communication for liquid fiow to the lower part of said first compartment from the lower part of another of said compartments and attording communication for vapor flow from the upper part of said first compartment to the upper part of said second compartment, said second partition having an open portion providing a liquid conductive passageway between said third compartment and the lower part of said second compartment, means defining a plurality of U-shaped vapor conduits each connecting the upper portions of said second and third compartments and each extending downwardly through said second partition from the upper part of said second compartment and then upwardly outside said second partition and within said third compartment, said conduits being at positions spaced about said second partition, and volumetric change-transferring means in said shell for transferring volumetric changes from inside to outside said shell.

9. In a thermally actuated pump of the type wherein alternating volumetric changes are produced by vaporizing and condensing liquid in separate portions of said pump, in combination, a liquid-tight outer shell, a cylindrical inner shell within said outer shell and defining therewith a pumping chamber, a cylindrical first partition extending downwardly from the top of said outer shell and concentric with said inner shell, means extending through said top of said outer shell into the space encompassed by said first cylindrical partition for vaporizing liquid within said encompassed space, a cylindrical second partition extending downwardly from the top of said outer shell between said inner shell and said first partition and separating the space therebetween into annular second and third compartments within which to collect and condense vapor, respectively, said first partition having openings at the upper and lower ends thereof providing communication between said encompassed space and said second annular compartment, said second partition having an opening at the lower end thereof providing communication between said second and third compartments, said inner shell having a flexible bottom wall for transmitting volumetric changes from inside said inner shell to said pumping chamber, said second partition having a vapor transfer passage therein extending from the upper portion of said second annular compartment to a point just above the lower end of said second compartment, a tube in said third compartment extending upwardly from the lower end of said vapor transfer passage to a point above the upper end of said second compartment, an outlet tube extending from outside said outer shell into said pumping chamber, and an inlet tube extending from outside said outer shell into said pumping chamber.

10. A thermally actuated pump of the type in which volumetric changes are produced in repetitive cycles by alternately vaporizing liquid in one region of the pump and condensing the vaporized liquid in another region of the pump comprising a rigid liquid-retaining shell enclosing said pump, said rigid shell having at least one opening therein enabling the transfer of volumetric changes from inside to outside said shell for producing a pumping action, said pump having an inner compartment within said shell defined =by wall portions including at least one W311 portion of heat conductive material for vaporizing liquid in said inner compartment by heat applied through said heat conductive material, said pump including a second compartment within said shell at least partially surrounding said first compartment, said second compartment extending above the bottom of said first compartment for collecting vapor formed in said first compartment, said shell including therein a vapor transfer passage from said first compartment to said second compartment for supplying the vapor to said second compartment, said pump in cluding a third compartment within said shell, said third compartment having a portion thereof at an elevation above said second compartment for condensing vapor supplied from said second compartment, said shell including therein a second vapor transfer passage extending from said second compartment to said third compartment, said second vapor transfer passage beginning at a point near the top of said second compartment and progressing downwardly to a level substantially below said point and then turning and progressing upwardly and communicating with said third compartment at a point substantially above said level, said upwardly progressing portion of said second vapor transfer passage being defined by wall portions including material of good heat conductivity in contact with the liquid in said third compartment, whereby said material is cooled by the liquid in said third compartment for producing condensation of vapor in said second vapor transfer passage, thereby to provide quiet operation by reducing condensation, and said shell including therein liquid transfer passages extending from said third compartment to the lower portion of said second compartment and extending to the lower portion of said first compartment from another of said compartments for supplying liquid to said first compartment.

i0 11. A thermally actuated pump of the type in which volumetric changes are produced in repetitive cycles by alternately vaporizing liquid in one region of the pump and condensing the vaporized liquid in another region of the pump comprising a rigid liquid-retaining shell enclosing said pump, said rigid shell having at least one opening therein enabling the transfer of volumetric changes from inside to outside said shell for producing a pumping action, said pump having an inner compartment within said shell defined by wall portions including at least one wall portion of heat conductive material for vaporizing liquid in said inner compartment by heat applied through said heat conductive material, said pump including a second compartment within said shell at least partially surrounding said first compartment, said second compartment extending above the bottom of said first compartment for collecting vapor formed in said first compartment, said shell including therein a vapor transfer passage fro-m said first compartment to said second compartment for supplying the vapor to said second compartment, said pump including a third compartment within said shell, said third compartment having a portion thereof at an elevation above said second compartment for condensing vapor supplied from said second compartment, said shell including therein a second vapor transfer passage extending from said second compartment to said third compartment, said second vapor transfer passage beginning at a point near the top of said second compartment and progressing downwardly to a level substantially below said point and then turning and progressing upwardly and communicating with said third compartment at a point substantially above said level, said shell including therein liquid transfer passages extending from said third compartment to the lower portion of said second compartment and extending to the lower portion of said first compartment from another of said compartments for supplying liquid to said first compartment, and said shell including at least one additional vapor transfer passage similar in configuration to said second vapor transfer passage, said additional vapor transfer passage extending from said second compartment to said third compartment in parallel flow relationship with said second vapor transfer passage, said additional vapor transfer passage being located at a different position in said shell from said second vapor transfer passage, whereby said pump is adapted to operate in a normal position as well as in a tipped position.

References titted in the file of this patent UNITED STATLS FATENTS 1,900,656 Munters Mar. 7, 1933 1,922,546 Lucia Aug. 15, 1935 2,015,240 Scott-Snell et al Sept. 24, 1935 2,399,803 Herbert May 7, 1946 2,653,552 Geeraert Sept. 29, 1953 2,757,618 IQCBIL; Aug. 7-, 1956 2,969,747 MacCracken Jan. 31, 1961 

1. IN A THERMALLY ACTUATED PUMP OF THE TYPE IN WHICH ALTERNATING VOLUMETRIC CHANGES ARE PRODUCED BY ALTERNATELY VAPORIZING LIQUID IN A FIRST PORTION OF SAID PUMP AND CONDENSING THE VAPORIZED LIQUID IN A SECOND PORTION OF SAID PUMP, IN COMBINATION, AN OUTER SHELL HAVING SPACE THEREIN, FIRST PARTITION MEANS IN SAID SHELL DEFINING A FIRST COMPARTMENT IN WHICH TO VAPORIZE LIQUID BY HEATING AND SECOND PARTITION MEANS IN SAID SHELL DEFINING A SECOND COMPARTMENT, SAID SECOND COMPARTMENT EXTENDING UPWARDLY IN SAID SHELL AT LEAST TO THE LEVEL OF THE TOP OF SAID FIRST COMPARTMENT AND BEING ADJACENT TO SAID FIRST COMPARTMENT IN WHICH TO COLLECT VAPOR FORMED IN SAID FIRST COMPARTMENT, SAID FIRST AND SECOND COMPARTMENTS TOGETHER ENCOMPASSING ONLY A PART OF THE TOTAL SPACE WITHIN SAID SHELL, AT LEAST A PART OF THE REMAINING SPACE INSIDE SAID SHELL CONSTITUTING A THIRD COMPARTMENT WITHIN WHICH TO CONDENSE VAPOR COLLECTED IN SAID SECOND COMPARTMENT, SAID THIRD COMPARTMENT HAVING A PORTION AT A HIGHER LEVEL THAN THE TOP OF SAID SECOND COMPARTMENT, SAID FIRST PARTION MEANS HAVING AN OPENING THEREIN AFFORDING COMMUNICATION FOR LIQUID FLOW BETWEEN THE LOWER PART OF SAID FIRST AND ONE OF SAID OTHER COMPARTMENTS, AND HAVING A SECOND OPENING THEREIN AFFORDING COMMUNICATION FOR VAPOR FLOW FROM 